Airflow deflector for tail gun turrets



Filed June 7, 1956 MIME/V702. WEA/DELL B IVG,

HTTORNEY AIRFLOW DEFLECTOR non TAIL GUN TTS Wendell B. Fehring, Wichita, Kans., assignor to Boeing Airplane Company, Wichita, Kans., a corporation of Delawarev Application June 7, 1956, Serial No. 589,969

4 Claims. (Cl. 89-37.5)

This invention relates generally to aircraft tail cone assemblies, and pertains more particularly to an airflow deflector for a gun turret mounted in such an assembly. The principal object of the present invention is to prevent or minimize the deflection of the tail gun turret from disturbing the flight of the aircraft on which such a gun turret is carried. Heretofore, the deflection or pivoting of a gun turret located in the tail of an airplane has caused the aircraft so equipped to yaw or to pitch depending on the direction of turret deflection. At high speeds this becomes a serious matter. Therefore, it is an aim of the invention to so divert or deflect a sufficient portion of the airflow past the limited path of movement of the gun turret in order that the swinging of the turret in both azimuth and elevation will have substantially no effect on the control of the crafts path of movement.

Another object of the invention is to provide a deflector .of the type described that will equalize the airflow around and past the limited path of movement of the gun turret when actuated into a deflecting position and which will conform and harmonize with the general conical configuration of the tail cone assembly when in a retracted position. In other Words, when the tail gun turret is not being used, as will be the case most of the time, the surfaces of the deflector will then follow the general contour lines of the tail cone assembly in this region.

Another object of the invention is to provide an effective airflow deflector of the foregoing character that will be of lightweight construction, yet sturdy enough to withstand the aerodynamic forces to which it is subjected.

Theinvention, together with other objects attending its production, will be more clearly understood when the following description is read in connection with the accompanying drawing, in which:

Figure 1 is a plan view of a tail cone assembly equipped with my airflow deflector, a portion of the assembly being broken away in order to reveal a complete actuating mechanism for one of the deflecting vanes;

v Figure 2 is a plan detail of one of the deflecting vanes when looking radially outwardly, and

' Figure 3 is a perspective view depicting the vanes in a divergent relation so that the tail gun assembly may be pivoted in anydesired angular direction.

Referring in detail to the drawing, the tail cone assembly has been denoted in its entirety by the reference numeral 10. For the purpose of discussion the tail assembly may be considered as comprised of three sections, although one of these sections, as will presently be made manifest, is actually supported on and movable with the tail gun turret designated generally by the numeral 12 as the turret is pivoted or deflected in its various angular directions during a target tracking and 2,915,948 Patented Dec. 8 1959 The first of the sections mentioned above, which constitutes the forward position of the tail cone assembly, bears the reference numeral 14. This section 14 need not be described in detail other than to say that it includes conventional skin material, such as aluminum, which has been riveted directly to the aft end of the planes fuselage. It is within this section 14-that the forward end of the gun turret 12 is mounted for pivotal movement in azimuth and elevation. Since gun mounts of this type are old and well known, no need exists herein for further description. It might be mentioned, though,

that the cone of fire for gun mounts of this type is in the (not visible) which attach to the turret structure located concentrically with respect to said ring member. From the above it will be appreciated that in one sense the cone tip 16 is a part of the gun turret 12 inasmuch as it is movable therewith (see the dotted line position of Figure 1 representing one maximum angle of deflection of the gun turret), but inasmuch as it serves as fairing when the gun turret is in a central, inactive position, election has been made to include it as a part of the tail cone assembly, especially as it produces a continuation of the overall conical effect.

Proceeding now to describe the third or intermediate sectionof the tail cone assembly 10, it is to be observed that this section is composed of a plurality of petals or vanes 20. As best seen from Figure 2, each vane 20 includes anouter panel 22 of aluminum, that is, the same material as that which the fixed section 14 and cone tip 16 is made. As can be discerned from all three figures the panels 22 taper rearwardly, and as can be seen from Figure 3 each panel is of arcuate cross-section corresponding in curvature at its opposite ends to that of the sections 14 and 16. To the inner side of the panel 22 (it being remembered that Figure 2 is a radial view looking outwardly) it is attached, as by rivets 24, a plate 26 of greater stiffness, such as thin gauge steel stock. Secured to the plate, as by welding, is a hinge arm 28, a portion thereof projecting forwardly beyond the panel 22. By reason of a clevis 30, one for each vane, aflixed to a ring member 32, preferably a part of the crafts fuselage, and a pin 34, the vanes 20 are rendered pivotal with respect to the sections 14, 16, as well as the longitudinal center line of the gun turret 12. Skin slots 36 in the section 14 permit unhampered accommodation of the arms 28.

For the purpose of moving the vanes 20 from a condition of convergence to one of divergence, there is an actuator for each vane in the form of a double acting cylinder 38 to which lead a pair of pressure. hoses 40 and 42. In Figure 1 only a single pair of such hoses is pictured, but it will of course be appreciated that there is a duplicate pair of hoses for each vane. All of the sets of hoses connect with a single solenoid operated valve 44 having a fluid supply line 46 and a fluid return line 48 associated therewith, these lines having connection with the aircrafts hydraulic pumping or compressed air system, as the case may be. For the purpose of remote energization of the solenoid valve 44 a pair of conductors 50, 52 lead forwardly to a suitably located control panel 1 or station.

Each hinge arm 28 equipped with 'a pair of spaced integral clevises 54, 56. The closed end of the cylinder 38 is articulatively connected to the clevis 54 by a pin 58. Projecting from the other end of the cylinder 38 is a piston rod 60, the free end of this piston rod having pivotal connection with one end of a bell crank 62 by means of apin 64. The other clevis 56 has one end of a link element 66 pivotally connected thereto by reason of a pin 68 and has its other end connected to the other end of the bell crank 62 by a pin 70. The bell crank 62 in turn is rendered pivotal about a fixed point by virtue of a pin 72 engaging a fixedly disposed clevis 74. Each clevis 74 may be attached at angular intervals to a ring member 76 indicated rather schematically as was the earlier mentioned ring member 32. Here again, the ring member 76 may be incorporated into the fuselage. Due to the provision of an extension or dog 78 on the link element ,66 which is engageable with one arm of the bell crank 62, the link element is prevented from moving beyond a predetermined point and each vane 20 will thereby be opened to the same extent as the other vanes.

Because of the simplicity of construction, the operation should be readily understandable. Therefore, only a brief explanation pertaining thereto should suflice. When not in use, the tail gun turret 12 will reside along a longitudinal or central axis, this central or inactive position being depicted in solid outline in both Figures 1 and 3. Through the medum of fluid pressure applied to the piston of the rod 60 via the various hoses 42 all of the vanes 20 will be maintained in a contracted or converging relationship. Under these conditions the adjacent longitudinal edges of the vanes 20 will mate or lie in a proximal relation with each other and the generally streamlined conical contour of the tail assembly will be preserved. The lower half of Figure 1 aptly illustrates this condition.

Now when the tail gun turret 12 is to be trained on a target to the rear of the plane, in preparation for this act the gunner energizes the solenoid valve 44, thus causing fluid to flow under pressure through the hose 40 with the other hose 42 now being made the return. This of course results in the piston rod 60 being extended outwardly and in so doing the bell crank 62 will be rocked about its pin 72 in a clockwise direction from its dotted line position (Figure 1) to its solid line position. This action forces all of the vanes 20 outwardly in unison. By proper design of the limit stops 78 each vane 20 will be deflected or pivoted to the same angle of divergence. Such a condition appears collectively in Figure 3, and from this figure it can be seen that an appreciable amount of deflective area is presented to the airstream so that the bulk of the air is diverted outwardly in the direction of the sequence of arrows 80 seen in Figure 1. Also, from Figure 1 it will be discerned that this airflow path is beyond the limited path of pivotal movement of the gun turret 12 and the cone tip 16, the dotted line position of the turret representing one maximum angle of deflection. Without the deflecting vanes 20, the effect on the airplanes set course owing to the swing of the gun turret into such an angular position can well be appreciated. While Figure 1 has been considered to be a top plan view, and therefore the dotted line position of the turret an azimuth swing to one side which without the instant invention would cause the airplane to yaw, it will also be appreciated that a swing in elevation would produce an undesired pitch without the. deflector arrangement forming the subject matter of the invention.

Consequently, it will be recognized that a good aerodynamic skin design is preserved when the gun turret 12 is not being used and the vanes 20 are brought inwardly into a juxtaposed relation with the cone tip 16. On the other hand, when use is to be made of the gun turret and the vanes spread into their divergent condition, then the turret operates in a shielded zone of less turbulent arr. Accordingly, the path of the aircraft, even at high speeds, is virtually unaifected by extreme swings of the turret.

Having described the invention with suflicient clarity to enable those familiar with this art to construct and use it, I claim:

1. The improvement in an aircraft fuselage tail cone assembly that has at its extreme rearward end a gun turret rearwardly directed and cantilevered .from the fuselage frame structure forward of said turret by pivotal supportingmeans operable to pivot said gun turret from a normal central position aligned generally with the fuselage tail longitudinal axis to various positions deflected at substantial angles to said longitudinal axis, comprising: said fuselage tail cone assembly having a movable tip portion having a generally frusto-conical skin and said tip portion being secured concentrically to and movable with said gun turret, said tail cone assembly having a fixed forward portion covered with a fixed skin, and said tail cone assembly having an intermediate portion between said fixed forward portion and said movable tip portion having a skin substantially completely formed by an annular series of juxtaposed, rearwardly-elongated, petal-like vanes; said frusto-conical skin of said movable tip portion, said fixed skin of said forward portion and said petal-like vanes of said intermediate portion, in said normal central postion of said turret and when said vanes have their normal inward position, together forming a continuous and faired fuselage tail cone skin adapted for streamlined movement of the air stream therealong; pivot means fixed relative to said fuselage frame structure pivotally connecting said vanes near their forward ends to said fuselage frame structure on axes permitting the rear ends of said vanes to be deflected radially outwardly and inwardly and restraining said vanes from movement in any other direction; and means operable to deflect said vanes outwardly whereby they act to deflect said air stream from the area of said movable tip portion and gun turret as said gun turret is deflected from said normal position thereof to shield the same from the action of said air stream.

2. The subject matter of claim 1 in which said means operable to deflect said vanes outwardly includes fluid actuated cylinders and vane moving linkage operated thereby, said linkage including means operative to limit the outward movement of said vanes to the same relative angular position from said normal inward position thereof.

3. The improvement in an aircraft having a fuselage tail cone assembly and having a fuselage frame structure, comprising: said fuselage tail cone assembly having a tip portion to be shielded on occasion from the action of air passing along said fuselage tail cone assembly, said tail cone assembly having a fixed forward portion covered with a fixed skin, and said tail cone assembly having an intermediate portion between said fixed forward portion and said tip portion having a skin substantially completely formed by an annular. series of juxtaposed, rearwardly: elongated, petal-like vanes; the skin of said tip portion, said fixed skin of said forward portion and said petal-like vanes of said intermediate portion, in normal position when said vanes have their normal inward position, together forming a continuous and faired fuselage tailcone assembly skin adapted for streamlined movement of the air stream along said fuselage tail cone assembly; pivot means fixed relative to said fuselage frame structure pivotally connecting said vanes near their forward ends to said fuselage frame structure on axes permitting the rear ends of said vanes to bedeflected radially outwardly and inwardly and restraining said vanes from movement in any other direction; and means operable to deflect said vanes outwardly whereby they act to deflect said air stream from the area of said tip portion to shield the same from the action of said air stream.

4. The subject matter of claim 1 in which said means Operable to deflect said vanes outwardly includes means References Cited in the file of this patent UNITED STATES PATENTS Meyers July 13, 1948 Browning Jan. 31, 1950 Norman June 13, 1950 6 Graham May 18, 1954 Thieblot Aug. 9, 1955 Kuhlman June 5, 1956 Black Aug. 20, 1957 FOREIGN PATENTS Italy Oct. 25, 1928 Italy July 20, 1935 Germany May 13, 1954 

